CNR1 and fragile X syndrome: Indeed, deletion of FMRP within a mouse model of FXS led to reduced production of 2-AG, decreasing activation of CB1 receptors in the central nervous system.20 CBD has been shown to increase 2-AG availability,22 potentially attenuating or reversing one of the biological mechanisms of abnormal cellular function in FXS.20 Importantly, CB1 protein expression appears unaffected in FMR1 knockout (KO) mice, suggesting that the downstream elements of endocannabinoid signaling can be engaged, even in the absence of FMRP.19